Characterization of Red Gypsum for Mineral Carbon Dioxide Sequestration

Red gypsum, a by-product from titanium dioxide manufacturing industry is a potential raw material for mineral carbonation. In this study, the physical and chemical characteristics of red gypsum have been evaluated using different analytical instruments. The XRD result showed that calcium sulfate dihydrate is the major component in the red gypsum, while as the XRF results, it is consisted of CaO (۳۲.۲ wt%), Fe۲O۳ (۲۸.۹۹ wt%) and SO۳ (۳۱.۶ wt%) along with some impurities. The mean particle size of the red gypsum (d۵۰) was obtained to be ۵۶.۰۳ μm with the average specific surface area of ۷.۰۱ m۲/g. As FESEM images, the red gypsum has tubular and prismatic crystals in its structure in which they are coated with iron oxide layers. The FT-IR result proved the presence of sulphate and iron oxide bonds which are related to CaSO۴ and Fe۲O۳. In general, the analytical results suggested that the red gypsum can be a very potential feedstock for mineral carbonation due to the presence of significant amount of calcium and iron.